Oil immersed transformer shell

Abstract

The utility model discloses an oil immersed transformer shell, and belongs to the technical field of transformers. The shell sequentially comprises an outer-layer skin, a middle functional layer and an inner-layer substrate from outside to inside; the middle functional layer contains a low-melting-point alloy plate and a phase change-expansion composite material, honeycomb convex steps are uniformly distributed on the surface of the alloy plate, the alloy plate, the inner layer and the outer layer form a vacuum cavity, and the cavity is filled with a composite material containing phase change microcapsules and expanded graphite; the melting point of the alloy plate is 150-250 DEG C, the alloy plate has the gradient fusing characteristic through topological optimization, and negative pressure is maintained in a cavity. According to the invention, accurate response can be realized during fault overtemperature, the phase change microcapsule rapidly absorbs heat, the expanded graphite forms a porous layer to attenuate shock waves and realize thermal invisibility, mechanical protection and function cooperation are considered, and the operation safety and fault handling capacity of the transformer are effectively improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to transformer technical field, concretely relates to a kind of oil-immersed transformer shell. BACKGROUND

[0002] As the core equipment of power system, the operation safety and stability of oil-immersed transformer directly determine the power supply reliability of power grid. As a key protection component, the transformer shell not only needs to bear mechanical protection and sealing insulation function, but also needs to realize efficient heat management and risk buffering under fault conditions. When the transformer generates local overheating due to internal short circuit, partial discharge and other faults, if the heat cannot be dissipated in time, it is easy to cause thermal decomposition and explosion of insulating oil, and even lead to the spread of shock wave, causing equipment damage and power grid outage.

[0003] The existing oil-immersed transformer shell is mostly made of single metal plate (such as steel plate) or simple composite structure (metal layer + insulation layer), which has two core technical defects: first, the heat management capability is insufficient. The traditional shell only relies on metal heat conduction and dissipation, lacks active heat absorption and temperature regulation mechanism, and local high temperature during fault is easy to break through the tolerance limit of the shell, accelerating the expansion of the fault. Second, the fault buffering performance is missing. When the shock wave is generated by the explosion of insulating oil caused by fault, the existing shell can only rely on its own structural strength to resist, cannot realize shock wave attenuation, and has no effective heat stealth means under high temperature, which is easy to cause the surrounding equipment to be affected by high temperature radiation.

[0004] Although some technologies try to add cooling fins or fill thermal insulation materials inside the shell, there are still obvious limitations: cooling fins can only enhance passive heat dissipation under normal working conditions, and it is difficult to quickly absorb heat during fault overheating; traditional thermal insulation materials have no expansion and adsorption properties, cannot form a buffer barrier when shock wave is generated, and are difficult to meet the dual needs of heat management and fault protection.

[0005] Therefore, in view of the deficiencies of the existing oil-immersed transformer shell in heat management and fault protection, it is urgent to develop a composite shell structure with active heat absorption, shock wave attenuation and heat stealth function to improve the operation safety and fault response capability of the transformer. UTILITY MODEL CONTENT

[0006] In view of the deficiencies in the background art, the utility model provides an oil-immersed transformer shell.

[0007] The technical scheme adopted by the utility model is: an oil-immersed transformer shell, comprising a transformer shell, the shell wall of the shell is sequentially stacked from outside to inside with an outer skin, an intermediate functional layer and an inner base plate;

[0008] The intermediate functional layer comprises a low-melting alloy plate and a phase change-expansion composite material, the low-melting alloy plate is provided with a plurality of honeycomb structure convex steps on the surface, the convex steps form a vacuum cavity between the outer skin and the inner base plate, and the vacuum cavity is filled with the phase change-expansion composite material; the melting point of the low-melting alloy plate is between 150 DEG C and 250 DEG C.

[0009] The vacuum cavity maintains a negative pressure state, and the phase change-expansion composite material filled in the vacuum cavity is a mixture containing phase change microcapsules and expanded graphite.

[0010] Further, the height of the convex steps of the honeycomb structure is 3-5 mm, and the interval is 10-15 mm.

[0011] Further, the low-melting alloy plate is made of Sn-Sb-Cu alloy, and is provided with a narrow neck weakened area at intervals, and the minimum thickness of the narrow neck weakened area is less than or equal to 0.5 mm.

[0012] Further, the capsule core of the phase change microcapsule is an organic alkane phase change material, and the capsule wall is a carbonated calcium-metallic copper double-shell structure doped with a low-infrared-emissivity filler.

[0013] Further, the outer skin is a quartz fiber reinforced silicon resin or a stainless steel foil honeycomb sandwich plate.

[0014] Further, the vacuum degree of the vacuum cavity is less than or equal to 0.1 Pa.

[0015] Further, the inner base plate is a galvanized steel plate or an aluminum alloy plate.

[0016] The utility model discloses the beneficial effect is:

[0017] 1. Efficient and accurate heat control: the low-melting alloy plate of the intermediate functional layer has a 150-250 DEG C gradient melting characteristic, and can accurately respond when a local temperature of the fault is too high; in the phase change-expansion composite material in the vacuum cavity, the phase change microcapsule can quickly absorb heat and phase change, and timely suppress the temperature rise, solving the problem of heat control failure of the traditional shell when a fault occurs.

[0018] 2. Double fault protection: after the low-melting alloy plate is melted and the vacuum cavity collapses, the expanded graphite rapidly forms a porous adsorption layer, which can effectively attenuate the shock wave generated by the combustion of insulating oil on one hand, and reduce the risk of equipment damage; on the other hand, the porous structure can achieve thermal stealth, reduce the influence of high-temperature radiation on surrounding equipment, and make up for the defect of the traditional shell without fault buffering capacity.

[0019] 3. Strong functional synergy adaptability: the composite structure of the outer skin, the intermediate functional layer and the inner substrate not only retains the mechanical protection and sealing insulation function of the shell base, but also realizes active heat absorption, shock wave attenuation and thermal stealth through the synergy of each functional layer, avoids the limitation that the heat dissipation and protection functions cannot be considered in the traditional technology, and significantly improves the operation safety and fault response capability of the transformer.

[0020] In addition to the purposes, features and advantages described above, the utility model has other purposes, features and advantages.

[0021] The utility model will be described in further detail below with reference to the drawings. DRAWINGS

[0022] Fig. 1 It is a structural schematic diagram of the utility model.

[0023] Fig. 2 It is a structural schematic diagram of the intermediate functional layer.

[0024] Figs. 1-2 M: 1, outer skin; 2, intermediate functional layer; 3, inner substrate; 4, boss step; 5, narrow neck weakening area. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the utility model will be described clearly and completely below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the utility model.

[0026] It should be noted that if the embodiments of the utility model involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement condition, etc. between the components in a certain specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0027] The utility model provides a kind of oil-immersed transformer shell.

[0028] In the embodiment, referring to Figs. 1-2 The oil-immersed transformer shell includes a transformer shell. The shell wall of the shell is sequentially stacked from outside to inside with an outer skin 1, an intermediate functional layer 2 and an inner substrate 3.

[0029] The intermediate functional layer comprises a low-melting alloy plate and a phase change-expansion composite material, the surface of the low-melting alloy plate is uniformly distributed with a plurality of honeycomb structure convex steps 4, the vacuum cavity is formed between the low-melting alloy plate and the outer skin and the inner base plate, and the vacuum cavity is filled with the phase change-expansion composite material; the melting point of the low-melting alloy plate is between 150 DEG C and 250 DEG C.

[0030] The vacuum cavity maintains a negative pressure state, and the phase change-expansion composite material filled in the vacuum cavity is a mixture containing phase change microcapsules and expanded graphite.

[0031] In the above technical solution, the shell adopts a three-layer composite structure of an outer skin, an intermediate functional layer and an inner base plate, and multiple functions are realized through interlayer cooperation: the outer skin provides basic protection, the inner base plate guarantees structural support, and the intermediate functional layer focuses on the core functions of heat control and fault protection.

[0032] In the intermediate functional layer, the honeycomb structure convex steps on the surface of the low-melting alloy plate form a vacuum cavity with the inner and outer layers, the vacuum cavity in a negative pressure state can reduce heat conduction and provide space for the phase change-expansion composite material; the low-melting alloy plate with a melting point of 150-250 DEG C can be preferably designed by topology optimization to have a gradient difference in melting temperature in different regions, so that it can be melted according to a preset order when a local fault overheats; in the phase change-expansion composite material, the phase change microcapsules can absorb heat through phase change of the core material, and the expanded graphite expands in volume to form a porous structure after being heated.

[0033] The low-melting alloy plate with the gradient melting feature realizes accurate response to overheating faults, avoids the failure of protection caused by synchronous melting of the whole, and can serve as a reinforcing framework and a heat dissipation channel during normal operation. Once the temperature rises sharply due to an internal fault (such as an electric arc), the alloy grid will selectively melt at the high-temperature point, like a fuse, to accurately start the entire protection. This controllable melting behavior is like a fuse, which accurately starts the entire protection sequence; the heat insulation effect of the vacuum cavity reduces heat loss under normal working conditions, the phase change microcapsules quickly absorb heat to inhibit the spread of high temperature caused by faults, and the expanded graphite forms a buffer layer after the cavity collapses, realizing the dual core functions of heat control and fault protection, and significantly improving the fault response capability of the transformer.

[0034] Specifically, the height of the convex steps of the honeycomb structure is 3-5 mm, and the pitch is 10-15 mm.

[0035] In this embodiment, the height (3-5 mm) of the honeycomb structure convex steps determines the volume of the vacuum cavity, which can accommodate sufficient phase change-expansion composite material to ensure the heat absorption and buffering effect, and also avoids increasing the overall thickness of the shell due to the excessive size of the cavity; the pitch (10-15 mm) design balances the structural strength and functional density, ensures that the convex steps can stably support the inner and outer layers, and also makes the composite material evenly distributed to avoid local functional defects.

[0036] Specifically, the low-melting alloy plate is made of Sn-Sb-Cu alloy, and is provided with a narrow-neck weakened area 5, and the minimum thickness of the narrow-neck weakened area is ≤0.5 mm.

[0037] In the embodiment, the selection of Sn-Sb-Cu alloy ensures that the low-melting alloy plate is accurately fused in the target temperature range, avoids response lag or false triggering caused by alloy melting point deviation, and guarantees the reliability of fault response. The design of the narrow-neck weakened area makes the gradient fusion characteristics incarnate, realizes orderly fracture when overheating, avoids the whole collapse leading to the instantaneous failure of the vacuum cavity, and improves the continuity of heat control and fault protection.

[0038] Specifically, the capsule core of the phase change microcapsule is an organic alkane phase change material, and the capsule wall is a double-layer shell structure of calcium carbonate-doped with low-infrared emissivity filler and metal copper.

[0039] In the embodiment, the organic alkane capsule core ensures that the phase change microcapsule efficiently absorbs heat and quickly suppresses the fault temperature rise, thereby improving the heat control efficiency; the double-layer capsule wall guarantees the stability of the microcapsule under normal working conditions and fault working conditions, thereby prolonging the service life. The combination of the low-infrared emissivity filler and the metal copper layer significantly reduces the infrared radiation characteristics of the shell, strengthens the heat stealth effect, reduces the radiation influence of high temperature on the peripheral equipment, and improves the safety of the overall system.

[0040] Specifically, the outer skin is a quartz fiber reinforced silicone resin or a stainless steel foil honeycomb sandwich panel.

[0041] Specifically, the vacuum degree of the vacuum cavity is ≤0.1 Pa.

[0042] In the embodiment, in the high vacuum state with a vacuum degree of ≤0.1 Pa, the number of gas molecules in the vacuum cavity is extremely small, and the heat conduction and convective heat transfer of the gas are greatly weakened, forming an efficient heat insulation barrier; at the same time, the high vacuum environment can avoid chemical reactions between the gas and the phase change-expansion composite material, thereby guaranteeing the stability of the material performance.

[0043] Specifically, the inner layer substrate is a galvanized steel plate or an aluminum alloy plate.

[0044] In the embodiment, the galvanized steel plate has good mechanical strength and corrosion resistance, and the zinc layer can effectively isolate air and moisture to prevent the steel plate from rusting; the aluminum alloy plate has the characteristics of lightweight, high strength, and moderate thermal conductivity, which can provide structural support without causing excessive heat loss under normal working conditions due to too fast heat conduction.

[0045] Skilled technicians should know: although the utility model has been described in the above specific embodiments, the utility model idea is not limited to this utility model, any modification using the utility model idea will be included in the patent protection range.

Claims

1. An oil-immersed transformer tank comprising a transformer tank, characterized in that The shell wall of the shell is sequentially stacked from outside to inside with an outer skin, an intermediate functional layer and an inner base plate; The intermediate functional layer comprises a low-melting-point alloy plate and a phase-change-expansion composite material, the surface of the low-melting-point alloy plate is uniformly distributed with a plurality of convex steps of honeycomb structure, the convex steps form a vacuum cavity between the outer skin and the inner base plate, the vacuum cavity is filled with the phase-change-expansion composite material; the melting point of the low-melting-point alloy plate is between 150-250℃; The vacuum cavity maintains a negative pressure state, and the phase-change-expansion composite material filled in the vacuum cavity is a mixture containing phase-change microcapsules and expanded graphite.

2. The oil-immersed transformer tank according to claim 1, characterized in that: The height of the convex steps of the honeycomb structure is 3-5mm, and the interval is 10-15mm.

3. The oil-immersed transformer tank according to claim 1, characterized in that: The low-melting-point alloy plate is made of Sn-Sb-Cu alloy, and is provided with a narrow-neck weakened area at intervals, and the minimum thickness of the narrow-neck weakened area is ≤0.5mm.

4. The oil-immersed transformer tank according to claim 1, characterized in that: The core of the phase-change microcapsule is an organic alkane phase-change material, and the wall is a double-shell structure of calcium carbonate-metallic copper doped with a low-infrared-emissivity filler.

5. The oil-immersed transformer tank according to claim 1, characterized in that: The outer skin is a quartz fiber reinforced silicone resin or a stainless steel foil honeycomb sandwich plate.

6. The oil-immersed transformer tank according to claim 1, characterized in that: The vacuum degree of the vacuum cavity is ≤0.1Pa.

7. The oil-immersed transformer tank according to claim 1, characterized in that: The inner base plate is a galvanized steel plate or an aluminum alloy plate.

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